If following this approach, andrei (with aphanes as a junior synonym) becomes a subspecies of Vaux's swift.

This placement, however, was considered mistaken by Restall et al. (2006), who state that andrei and aphanes, while virtually identical under normal field conditions, actually do differ and also have different behavior and habitat preferences (ashy-tailed swift prefers forested lowland rivers, while Vaux's swift race aphanes prefers mountain slopes).

[5] As of early 2020, taxonomists retained ashy-tailed as a subspecies of Vaux's swift.

The ashy-tailed's throat and abdomen tend to be browner than those of Vaux's, the back lighter brown, and the rump paler.

The species' call is described as a "[h]igh-pitched, rapid chipping and buzzy insect-like twitter given in flight.